1. Field of the Invention
The present invention relates to a filling amount adjustment device that controls the amount of filling in a liquid-form substance filling machine that supplies a liquid-form substance via filling nozzles to bags held in an automated packaging machine.
2. Prior Art
Japanese Utility Model Application Publication (Kokoku) No. S62-40882 discloses a liquid-form substance filling machine that includes a storage tank for a liquid-form substance, a switch-over valve, a filling nozzle, a filling cylinder, etc. In this liquid-form substance filling machine, the piston rod of the filling cylinder is raised and lowered via a crank driving section and an L-shaped lever. A predetermined amount of a liquid-form substance is supplied into the filling cylinder, and then the liquid-form substance is discharged from the filling cylinder and then released out of the filling nozzle.
The above liquid-form substance filling machine further includes a rough adjustment mechanism and a fine adjustment mechanism for the filling amount. The rough adjustment mechanism is installed in the crank driving section. It adjusts the pivot angle of the L-shaped lever with the attachment position of the crank pin being adjustable in the radial direction by a screw. The fine adjustment mechanism is installed on the L-shaped lever. It adjusts the distance from the pivoting center with the attachment position of a connected rod connected to the piston rod being freely adjustable in the direction of length of the lever by a screw. The attachment positions of the respective adjustment mechanisms are adjusted by manually turning knobs that are attached to the end portions of the screws.
Japanese Utility Model Application Laid-Open (Kokai) No. H05-44801 discloses an improvement of the above-described fine adjustment mechanism. Instead of turning the screw by a knob, a gear is attached to the end portion of the screw, and this gear is driven by a motor that has a speed reduction gear and is disposed on the L-shaped lever.
The adjustment by the above-described rough adjustment mechanism is performed when the filling amount changes. This adjustment is ordinarily performed while the automated packaging machine and filling machine are stopped. However, the adjustment by the fine adjustment assembly is often performed while the system is in operation. In other words, fine adjustment is performed when variation in the filling amount that accompanies changes in the properties (viscosity and temperature) of the liquid-form substance during operation is corrected. Fine adjustment is also performed when the filling amount is accurately set while sampling is performed in the case of a change in the type of liquid-form substance that is to be handled.
However, in the filling amount adjustment device described in Japanese Utility Model Publication (Kokoku) No. S62-40882, the L-shaped lever constantly swings during the operation of the filling machine. Thus, it is actually very dangerous and practically impossible to adjust the filling amount by manually turning the knob of the fine adjustment assembly. As a result, not only is there a drop in the working efficiency, i.e., a drop in productivity, but it is also extremely difficult to obtain an accurate filling amount.
On the other hand, in the filling amount adjustment device described in Japanese Utility Model Application Kokai (Laid-Open) No. H05-44801, the fine adjustment assembly is driven by a motor that is equipped with a speed reduction gear. This device is advantageous in that fine adjustment is done even during the operation of the filling machine.
However, if the motor equipped with a speed reduction gear is disposed on the L-shaped lever in the configuration described in the above-described Japanese Utility Model Publication (Kokoku) No. S62-40882, the motor is positioned directly beneath the filling cylinder. As a result, a motor trouble would easily occur by a leaking liquid.
Furthermore, the moving element increases in size, and the space available for avoiding interference with other elements inside the machine becomes insufficient (the crank driving section and L-shaped lever, etc., are accommodated inside a cramped machine base together with the driving mechanism and control device of the packaging machine proper). Especially for a multi-unit type packaging machine (in which a plurality of bags are simultaneously supplied, and respective packaging is successively performed on a plurality of bags at the same time in order to improve productivity), it is necessary to install an L-shaped lever, on which a motor equipped with a speed reduction gear is disposed, for the piston rod of each one of the filling cylinders. As a result, the problem of insufficient space inside the machine base becomes even more critical. In addition, since the installed plurality of heavy motors make swing movements, the load on the crank driving section and on the driving force transmission mechanism is extremely large.
Accordingly, the present invention is to solve the above-described problems with the conventional devices.
It is thus an object of the present invention to provide a filling amount adjustment device that allows adjustment of the filling amount even while the filling machine is in operation.
It is another object of the present invention to provide a filling amount adjustment device that is free of an excessively large installation space even when used in a multi-unit type packaging machine.
It is still another object of the present invention to provide a filling amount adjustment device that prevents excess load on the drive section and transmission mechanism.
The above objects are accomplished by a unique structure for a filling amount adjustment device used in a liquid-form substance filling machine in which a piston rod is caused to advance and retract by an arm that is connected to a drive section and makes a swing movement, a piston is caused to advance and retract inside a filling cylinder by the piston rod, a predetermined amount of a liquid-form substance is supplied into the filling cylinder, and the liquid-form substance is discharged from the filling cylinder and then released out of a filling nozzle; and the filling amount adjustment device of the present invention comprises:
a first sliding member provided on the arm so that the first sliding member swings together with the arm and slides in a direction of length of the arm, the first sliding member being connected to the piston rod via a connecting member,
a second sliding member which slides in a direction perpendicular to a supporting shaft of the arm and stops at appropriate positions, and
a position regulating member which is provided on the second sliding member and is moved by a sliding movement of the second sliding member, the position regulating member being connected to the first sliding member and guiding a swing movement of the first sliding member along a predetermined path, wherein
the position of the first sliding member with respect to the direction of length of the arm is adjusted by way of sliding the second sliding member and thus moving the position regulating member.
In a desirable configuration of the present invention, the position regulating member is a connecting link, one end of this connecting link is pivotally connected to the first sliding member, and another and of this connecting link is pivotally attached to the second sliding member. Alternatively, the position regulating member can be a grooved cam. This position regulating member or the grooved cam is connected to the first sliding member via a cam roller which rolls in the groove of the grooved cam.
Furthermore, the present invention is applicable to a multi-unit type liquid-form substance filling machine which is equipped with a plurality of filling cylinders and filling nozzles. In this case, a plurality of first sliding members are installed on a single arm, and the second sliding members and position regulating members are installed so as to correspond to the respective first sliding members. The positioning of the plurality of second sliding members is accomplished for each one of the second sliding members.